Add `useCanvasIsBusySafe()` hook. This is like `useCanvasIsBusy()`, but when the canvas is not initialized, it gracefully falls back to false instead of raising.
Because app tabs are lazy-loaded, the canvas is not initialized until the user visits that tab. If the page loads up on the workflows tab, the canvas will be uninitialized until the user clicks on it.
This graceful fallback behaviour allows actions like sending an image to canvas to work even when the canvas is not yet initialized. These actions are exposed in the image context menu, and previously were hidden when the canvas was not initialized. We can now show these actions and use them even when the canvas is uninitialized.
- Add `useCanvasIsBusySafe()` hook
- Use the new hook in the image context menu for send to canvas actions
- Do not use `<CanvasManagerProviderGate />` in the image context menu (this was hiding the actions when canvas was uninitialized)
